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Unformatted text preview: the height 2) the same height 3) 2 times the height 4) twice the height 5) four times the height Use energy conservation: initial energy: Ei = PEg = mgH final energy: Ef = KE = 1/2 mv2 Conservation of Energy: Ei = mgH = Ef = 1/2 mv2 therefore: gH = 1/2 v2 So if v doubles, H quadruples! ConcepTest 8.7b Runaway Box
A box sliding on a frictionless flat surface runs into a fixed spring, which compresses a distance x to stop the box. If the initial speed of the box were doubled, how much would the spring compress in this case? 1) half as much 2) the same amount 3) 2 times as much 4) twice as much 5) four times as much x ConcepTest 8.7b Runaway Box
A box sliding on a frictionless flat surface runs into a fixed spring, which compresses a distance x to stop the box. If the initial speed of the box were doubled, how much would the spring compress in this case? 1) half as much 2) the same amount 3) 2 times as much 4) twice as much 5) four times as much Use energy conservation: initial energy: Ei = KE = 1/2 mv2 final energy: Ef = PEs = 1/2 kx2 Conservation of Energy: Ei = 1/2 mv2 = Ef = 1/2 kx2 therefore: mv2 = kx2 So if v doubles, x doubles! x ConcepTest 8.9...
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This note was uploaded on 05/13/2010 for the course PHYSICS 53L taught by Professor Mueller during the Fall '07 term at Duke.
 Fall '07
 Mueller
 Physics, Energy, Potential Energy

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